[Document 1] Korean Patent Application Publication No.: 10-2004-0084412.                Pub. Date: Oct. 6, 2004        
[Document 2] U.S. Pat. No. 9,440,573 (Issue Date Sep. 13, 2016)
The Prior Art Document 1 teaches a cup holder for automobile with a structure having a tray for supporting a cup and a hole formed through the tray, so as to receive a cup by inserting it in the hole.
The Prior Art Document 2 teaches a cup holder assembly, which includes a pair of planar bodies each defining a rim, and a pair of fabric pouches that are each attached to one of the rims. The planar bodies are pivotably attached to each other and are configured such that, in a folded position, the rims are stacked and the fabric pouches are nested within each other, and in a deployed position, the rims and fabric pouches are side-by-side.
Conventional cup holder structure that relates to the invention is as follows. For example, a cup inserted to a ring-shaped cup holder is provided to a customer for preventing hot portion from touching in the case of only one cup for take-out of coffee. However, in order to pack two or more of them, a portable cup holder for take-out that is made of paper material has been used. However, lots of paper material is needed for the cup holder and the cup tends to be detached or escape from the cup holder due to the weight of contents of the cup when handled in wrong ways. Also, the contents in the cup held in the cup holder may be spilled, for the cup could be shaken in the inner space of the cup holder.
Also, as for the cup holders of such paper material, the folding assembly process is inconvenient and time-consuming and the structure makes the manufacturing processes complicated, resulting in an increase of manufacturing cost. Also, since the volume of the cup holder is big, it is not easy to load, transport, and store, resulting in an increase of logistic cost.